Collets are used in conjunction with cutting machines such as lathes and drill presses to secure a cutting tool such as a drill bit in place when machining a workpiece. The cutting tool is inserted into one end of the collet and the opposed end of the collet is inserted into a tool holder of a cutting machine.
In order to provide a secure fit for the cutting tool within the collet, the collet is typically made with a series of spaced apart axial slits around the circumference of the collet. Typically, there are alternating series of slits wherein one of the series of slits opens into the end of the collet which is inserted into the cutting machine and the next slit in the series opens into the end of the collet which receives the cutting tool. These alternating slits make it possible for the collet to expand or contract around the cutting tool thereby providing a secure fit.
As is well known, collets are used in conjunction with machines and/or workpieces that rotate at great speeds to obtain accurate and smooth cuts. Accordingly, a high degree of frictional force is developed at the cutting site resulting in high temperatures. It is therefore necessary to continuously cool and/or lubricate the workpiece to avoid tool and workpiece failure.
Heretofore such cutting machines have been equipped with externally mounted cutting fluid systems which provide a continuous supply of cutting fluid to the workpiece. Such systems typically have a hose and a nozzle directed at the workpiece. The hose and nozzle are affixed to the outside of the cutting machine and may automatically shut off when the cutting operation is terminated.
Such cutting fluid systems, however, suffer from major disadvantages. They are expensive to install and thereby add greatly to the cost of the basic cutting machine. Further, since cutting fluid systems are mounted externally to the machine itself, they are subject to breakdowns due to inadvertant damage caused by operators working with the cutting machine.
The present invention overcomes these disadvantages by providing a collet having a transverse channel connecting the existing expansion axial slits to provide a continuous pathway for the flow of the cutting fluid from the cutting machine through the collet to the workpiece. As a result of the present invention, the external cutting fluid systems are eliminated and there is a more even distribution of the cutting fluid to the workpiece.
It is therefore an object of the present invention to provide a collet for holding a cutting tool which also provides a pathway for the even and continuous flow of a cutting fluid from a cutting machine to a workpiece.
It is a further object of the invention to provide a means for eliminating the external cutting fluid systems which are typically used in conjunction with cutting machines.